The present invention relates to a sound insulating device for reducing noise from vehicles, trains and the like in expressways or railroads, or other sound sources.
Conventionally, a sound insulating device in which a plurality of plate shaped sound insulating members is attached to an H-shaped steel beam arranged in an upstanding manner in plural numbers along a road, a railway track, and the like, and this sound shielding member is arranged in a form of a wall surface is known.
This type of sound insulating device has an advantage in that the configuration is simplified, the number of components is few, and the workability is satisfactory since the sound insulating member is stacked in plural numbers in an up and down direction by fitting both ends from above the H-shaped steel beam when being attached to the H-shape steel beam so that the sound insulating member is directly attached to the H-shaped steel beam.
Such sound insulating device includes a railroad soundproof wall arranged on a ground along the track of the railroad vehicle, forming a sound absorbing surface on the surface facing the track of the upstanding wall part, and absorbing rolling noise of the wheels and noise from the motor (see for example, patent document 1).
The sound absorbing panel at this soundproof wall is made by filling sound absorbing materials such as glass wool inside a flat box having a sound absorbing surface side of the front surface as porous plate and the rear surface as steel plate, and this sound absorbing panel is attached by being stacked vertically with respect to a supporting column arranged on the track.
In addition, a sound insulating wall arranged on the road or the railroad is known, where the sound insulating wall is attached to the upstanding H-shaped steel beam by stacking a plurality of panel shaped sound absorbing plates, in which sound absorbing materials are filled in a box frame, in the up and down direction (see for example, patent document 2).
The sound insulating wall aims to enhance air tightness by interposing an elastic air tight member on the contacting surface of the sound absorbing plate in addition to the sound absorbing plate stacked in the up and down direction, and to prevent sound leakage.
This sound insulating member in such sound insulating wall incorporates sound absorbing materials such as glass wool and cotton in the box shaped case having a great number of sound absorbing holes perforated in the front surface, or sandwiches the same with a louver, and aims to insulate sound by absorbing noise at the sound absorbing material.
[Patent document 1] Japanese Publication No. 3660335
[Patent document 2] Japanese Laid-Open Patent Publication No. 2004-132018
The soundproof wall described in patent document 1 and patent document 2 attempts to absorb noise by means of sound absorbing material, but since both front surface and rear surface of the aluminum plate materials sandwiching the sound absorbing material contact with the sound absorbing material because of its structure when the sound absorbing material is used, the sound wave easily reflects and lowers the sound absorbing efficiency.
Furthermore, when sound absorbing materials such as glass wool and cotton are used, moisture such as rainwater and snow is absorbed since such sound absorbing material has water retention characteristics, and thus the sound absorbing performance temporary lowers. Furthermore, the sound absorbing material degrades by absorption of such moisture, whereby the sound absorbing performance becomes difficult to maintain over a long period and maintenance such as repair and replacement must be carried out frequently to maintain the sound absorbing performance.
In addition, such soundproof wall requires a gap to be filled with a different sound absorbing member sandwiched between a flange of the H-shaped steel and the sound insulating member, or the sound insulating member to be fixed to the H-shaped steel by a bolt and the like to fix the sound insulating member to the H-shaped steel beam when attaching the sound insulating member to the H-shaped steel beam, and thus assembly workability gradually degrades. Furthermore, since the sound absorbing material is used, problems such as the weight increasing, and the number of components increasing occurs.
Problems such as the sound shielding member having a complicated configuration, the manufacturing becoming difficult, and cost increases occur since it is configured by a plurality of members as described above. When the sound insulating member breaks, the sound absorbing material must be disposed as industrial waste, and thus a problem in that the processing cost increases occurs.
The present invention is developed to overcome the problems of the prior art, and aims to provide a sound insulating device that exhibits excellent sound insulating property, which sound insulating device is capable of maintaining this sound insulating property over a long period, excels in assembly workability, and is easily manufactured and readily disposed of.